Camera system for recording images, and associated method

ABSTRACT

In the case of a camera system for recording images consisting of at least one single camera, a solution is intended to be provided which allows a good sharp image to be recorded. This is achieved by virtue of the single cameras ( 1 ) each being arranged in different directions such that they record a continuous overall image, with the overall image comprising the frames from the single cameras ( 1 ), and are being a central control unit ( 3 ) which can be used to capture the motion profile of the camera system by means of at least one sensor ( 2 ) and to ascertain the trigger times of the single cameras ( 1 ) on the basis of a prescribed target function, said camera system moving autonomously over the entire time progression.

This application is a National Stage of PCT/DE2012/000464, filed Apr.30, 2012, which claims priority to German Patent Application No, 10 2011109 990.9, filed Aug. 8, 2011 and German Patent Application No. 10 2011100 738.9, filed May 5, 2011, the disclosures of each of which areincorporated herein by reference in their entireties.

The invention is directed to a camera system of capturing imagesconsisting of at least a single camera.

The invention is further directed to a method of capturing images usinga camera system comprising at least a single camera and at least acontrol unit, and a sensor, in particular an accelerometer.

Panoramic images allow us to capture images that come close to the humanvisual field. They thus enable a better overall impression of a placethan images of normal cameras. Panoramic cameras allow capturing suchpanoramic views by using a single camera or several single cameras. Theimages of several single cameras can be later assembled into aseamlessly composite image.

For cylindrical panoramas, special cameras exist that can project thescenery on an analog film or digital imaging sensor. Incompletespherical panoramas can be imaged by photographing a suitably shapedmirror (e.g. ball) and distortion can subsequently be corrected. U.S.Pat. No. 3,505,465 describes a catadioptric video camera that enables a360° panoramic view.

Fully spherical panoramas can be created by capturing single images andsubsequently assembling them (automatically) by a computer. Thereby, theimages can be captured either simultaneously by multiple cameras orsequentially with a single camera.

A single camera can be rotated to take overlapping images that can beassembled later. This principle works with a normal lens, fish-eyelenses and catadioptric systems.

In order to circumvent problems caused by time shifted image capturingsof a single camera, multiple cameras can be mounted to cover the fullsolid angle of 4 pi (Π) sr. In this case the visual field of the camerasoverlap and allow a later assembly of individual images.

In U.S. Pat. No. 7,463,280 an omnidirectional 3-D camera system isdescribed which is composed of several single cameras. U.S. Pat. No.6,947,059 describes a stereoscopic omnidirectional camera systemcomposed of multiple single cameras. U.S. Pat. No. 5,023,725 disclosesan omnidirectional camera system in which the single cameras arearranged as a dodecahedron.

The term “camera tossing” describes throwing normal cameras using atimer with preset delay for taking a photograph during flight. Severaldesign studies for panoramic cameras exist, as well as for singlecameras that are thrown or shot into the air.

“Triops” is the concept of a ball with three fish-eye lenses. The“CTRUS” football is supposed to integrate cameras into the surface of afootball. The “I-Ball” design consists of two fish-eye lenses integratedinto a ball to be thrown or shot in the air.

In the prior art, there are single cameras to be tossed in the air.“Flee” is a ball with a tail feather. “SatuGO” is a similar conceptwithout a tail feather.

It has not been described so far how to obtain a good sharp image withthese cameras that are tossed in the air.

The objective of this invention is to provide a solution that enableseach single camera to capture a good and sharp image, wherein the imagescan then assembled to an omnidirectional panoramic image. The solutionis provided through a system of integrated cameras.

The present invention solves the problem by the features of theindependent claims 1 through 15. Advantageous embodiments are describedin the dependent claims.

The present invention solves the problem by providing the aforementionedcamera system, wherein single cameras are each oriented into differentdirections so that they capture a composite image without gaps, whereinthe composite image comprises single images of the single cameras, andwherein a central control unit is arranged, which enables registering amotion profile of the camera system by at least one sensor anddetermining the moment of triggering the single cameras according to apredetermined objective function, wherein the camera system movesautonomously over the entire time span. Such a camera system enables anautonomous triggering of the single cameras according to an objectivefunction using a panoramic camera, e.g. when it is thrown into the air.

In one embodiment of the invention, the sensor is an accelerometer. Thisenables measuring the acceleration during throwing of a panoramic camerainto the air and to using the acceleration to determine the moment oftriggering the single cameras according to an objective function.

In another embodiment of the invention, the sensor is a sensor formeasuring the velocity relative to the ambient air. Thus, image capturescan be triggered according to an objective function which dependsdirectly on the actual measured velocity of the camera system.

To trigger the camera system at a predetermined position it isadvantageous that the objective function determines triggering thesingle cameras when the camera system falls short of a minimum distanced from the trigger point within the motion profile; an aspect thepresent invention further provides for.

In one embodiment of the invention, the camera system is preferablytriggered at the apogee of a trajectory. At the apogee, the velocity ofthe camera system is 0 m/s. The closer the camera system triggers atthis point, the slower it moves, resulting in less motion blur on thecaptured image.

The apogee also provides an interesting perspective, a good overview ofthe scenery and reduces parallax error due to smaller relative distancedifferences e.g. between ground and thrower.

In a further embodiment of the invention, the minimum distance d is atmost 20 cm, preferably 5 cm, in particular 1 cm. If the trigger point isthe apogee within a trajectory, it is advantageous that the camerasystem triggers as close to the point of momentary suspension aspossible.

In one embodiment of the invention, the single cameras are preferablyarranged that they cover a solid angle of 4 pi sr. Thus the camerasystem is omnidirectional and its orientation is irrelevant at themoment of image capture. Handling of the camera system is thereforeeasier compared with only a partial coverage of the solid angle, becausethe orientation is not important. In addition, the full sphericalpanorama allows viewing the scenery in every direction.

In another embodiment of the invention, the camera system comprises asupporting structure, and recesses in which the single cameras arearranged, wherein the recesses are designed so that a finger contactwith camera lenses is unlikely to occur or impossible, wherein a paddingmay be attached to the exterior of the camera system. Lens pollution ordamage is prevented by the recessed single cameras. Padding can bothprevent the damage of the single cameras as well as the damage of thecamera system as a whole. The padding can form an integral part of thesupporting structure. For example, the use of a very soft material forthe supporting structure of the camera system is conceivable. Thepadding may ensure that touching the camera lens with fingers is madedifficult or impossible. A small aperture angle of the single cameras isadvantageous allowing the recesses in which the single cameras arelocated to be narrower. However, more single cameras are needed to coverthe same solid angle in comparison to single cameras with a largeraperture angle.

In yet another embodiment of the invention, the camera system ischaracterized in that at least 80%, preferably more than 90%, inparticular 100% of the surface of the camera system form light inletsfor the single cameras. When images of several single cameras areassembled (“stitching”) into a composite image, parallax error is causeddue to different centers of projection of the single cameras. This canonly fee completely avoided if the projection centers of all singlecameras are located at the same point. However, for a solid anglecovering 4 pi sr it can only be accomplished, if the entire surface ofthe camera system is used for collecting light beams. This is the casefor a “glass sphere”. Deviations from this principle result in a loss oflight beams which pass through the surface aligning with the desiredcommon projection center. Thus parallax errors occur. Parallax errorscan be kept as small as possible, if the largest possible part of thesurface of the camera system is composed of light inlets for the singlecameras.

In order to align the horizon when looking at the composite image, it isexpedient to determine the direction of the gravity vector relative tothe camera system at the moment of image capture. Since the camerasystem is in free fall with air resistance during image capture, thegravity vector cannot be determined or can very difficult be determinedaccurately with an accelerometer. Therefore, the described camera systemmay apply a method in which the gravity vector is determined with anaccelerometer or another orientation sensor such as a magnetic fieldsensor before the camera system is in flight phase. The accelerometer ororientation sensor is preferably working in a 3-axis mode.

The change in orientation between the moment in which the gravity vectoris determined and the moment in which an image is captured can bedetermined using a rotation rate sensor, or another sensor that measuresthe rotation of the camera system. The gravity vector in relation to thecamera system at the moment of image capture can be easily calculated ifthe change in orientation is known. With a sufficiently accurate andhigh resolution accelerometer it may also be possible to determine thegravity vector at the moment of image capture with sufficient accuracyfor viewing the composite image based on the acceleration influenced byair friction and determined by the accelerometer, provided that thetrajectory is almost vertical.

In a further embodiment of the invention, the camera system comprises atleast one rotation rate sensor, wherein the central control unitprevents triggering of the single cameras if the camera system exceeds acertain rotation rate r, wherein the rotation rate r is calculable fromthe desired maximum blur and used exposure time, in little illuminatedsceneries or less sensitive single cameras, it may be useful to pass thecamera system several times into the air (eg, to throw) and only triggerin case the system does not spin strongly. The maximum rotation rate toavoid a certain motion blur can be calculated by the exposure timeapplied. The tolerated blur can be set and the camera system can bepassed several times into the air until one remains below the calculatedrotation rate. A (ball-shaped) camera system can easily be thrown intothe air repeatedly, which increases the chance of a sharp image over asingle toss.

At first, the luminance in the different directions must be measured forsetting the exposure. Either dedicated light sensors (such asphotodiodes) or the single cameras themselves can be used. Thesededicated exposure sensors that are installed in the camera system inaddition to the single cameras should cover the largest possible solidangle, ideally the solid angle of 4 pi sr. If the single cameras areused, one option is to use the built-in system of the single cameras fordetermining exposure and transferring the results (for example in theform of exposure time and/or aperture) to the control unit. Anotheroption is to take a series of exposures with the single cameras (e.g.different exposure times with the same aperture) and to transfer theseimages to the control unit. The control unit can determine the luminancefrom different directions based on the transferred data and calculateexposure values for the single cameras. For example, a uniform globalexposure may be aimed at or different exposure values for differentdirections may be used. Different exposure values can be useful to avoidlocal over- or underexposure. A gradual transition between light anddark exposure can be sought based on the collected exposure data.

Once the exposure values are calculated (exposure time and/or aperture,depending on the single cameras used), they are transmitted to thesingle cameras. The measurement of the exposure and the triggering ofthe single camera for the actual photo can be done either during thesame flight or in successive flights. If the measurement of the exposureand triggering for the actual photo is made in different flights, it maybe necessary to measure the rotation of the camera between these eventsand to adjust the exposure values accordingly, in order to trigger witha correct exposure in the correct direction.

Furthermore, the above problem is solved through a method of capturingimages using a camera system of the type described above. The inventiontherefore also provides a method characterized in that the moment oftriggering for the single cameras is determined by integrating theacceleration in time before entry into free fall with air resistance,and that the triggering of the single cameras occur after falling shortfrom a minimum distance to the trigger point within the trajectory, orupon detection of the free fall with air resistance, or upon a change ofthe direction of the air resistance at the transition from the rise tothe descent profile, or upon drop of the relative velocity to theambient air below at least 2 m/s, preferably below 1 m/s, in particularbelow 0.5 m/s, wherein either an image comprising at least a singleimage is captured by the single cameras or a time series of images eachcomprising at least one single image is captured by the single cameras,and the control unit evaluates the images in dependence on the contentof the images and only one image is selected.

The state of fee fall with air resistance of a camera system transferredinto the air (tossed, shot, thrown, etc.) occurs when no external forceis applied apart from gravity and air resistance. This applies to athrown system as soon as the system has left the hand. In this state, anaccelerometer will only detect acceleration due to air resistance alone.Therefore, it is appropriate to use the acceleration measured before thebeginning of the free fall in order to determine the trajectory. Byintegrating this acceleration, the initial velocity of flight and theascending time to a trigger point can be calculated. The triggering canthen be performed after expiration of the ascending time.

Another possibility is to evaluate the acceleration measured duringascent and descent due to air resistance. The acceleration vectordepends on the actual velocity and direction of flight. The currentposition in the trajectory can be concluded from evaluating the timecourse of the acceleration vector. For example, one can thereby realizetriggering at the apogee of a flight.

The actual position in the trajectory can also be concluded frommeasuring the relative velocity to the ambient air directly; and thecamera system can trigger e.g. if it falls short of a certain velocity.

When triggered, the camera system can capture either a single image(consisting of the individual images of the single cameras), or a seriesof images, for example, captured in uniform time intervals.

In this context it may also be useful to start triggering a series ofimage capture events directly after detecting free fall with airresistance, for example by an accelerometer.

In one embodiment of the invention the image is selected from the timeseries of images by calculating the current position of the camerasystem from the images, or by the sharpness of the images, or by thesize of the compressed images.

By analyzing the image data of a series of images, it is possible tocalculate the motion profile of the camera system. This can be used toselect an image from the series of images. For example, the imagecaptured when the camera system was closest to the apogee of the flightcan be selected.

According to the invention it is particularly useful that the singlecameras are synchronized with each other so that they all trigger at thesame time. The synchronization ensures that the single images match bothlocally and temporally.

To produce good and sharp images single cameras with integrated imagestabilization can be used in the camera system. These can work forexample with motile piezo-driven image sensors. For cost savings and/orlower energy consumption it may be expedient to use the sensorsconnected to the control unit, in particular the rotation rate sensors,for determining control signals for image stabilization systems of thesingle cameras. Thus, these sensors do not have to be present in thesingle cameras and the single cameras can remain turned off for a longertime.

Further, the sharpness of the images can foe analyzed to directly selecta picture with as little motion blur as possible. The consideration ofthe size of compressed images can lead to a similar result becausesharper images contain more information and therefore take up more spacein the data storage at the same compression rate.

According to one embodiment of the invention, once the rotational rate ris exceeded (wherein the rotational rate r can be calculated from theexposure time and the desired maximum motion blur), the triggering ofthe single cameras is suppressed or images are buffered from a pluralityof successive flights and the control unit controls the selection ofonly one of these images, wherein the image is selected based on theblur calculated from the image content, or based on the measuredrotational rate r, or based on the blur calculated from its measuredrotational rate r and the used exposure time. Thus, a user can simplythrow the system repeatedly into the air and obtains a sharp image withhigh probability.

To obtain a single sharp image with as little motion blur as possible byrepeatedly throwing the camera system into the air, two basic approachesare possible. Either the camera system triggers only below a certainrotation rate r and indicates image capturing visually or acoustically,or images of several flights are buffered and the image with the leastblur is selected from this set of images.

If triggering is suppressed when exceeding a rotational rate r, thisrate of rotation can be either chosen manually or calculated. It can becalculated from a fixed or user-selected maximum motion blur and theexposure time applied. For the calculation one can consider as how manypixels would be exposed by a point light source during exposure.

In the case of buffering, the control unit decides on the end of aflight series. This decision may be made due to a temporal interval(e.g. no flight/toss over several seconds) or by user interaction, suchas pressing a button. For selection of the image from the series ofimages several methods are possible. First, the blur caused by therotation can be determined from the image contents using imageprocessing and the sharpest image can be selected. Second, the measuredrotational rate r can be used, and the image with the lowest rotationrate r can be selected. Third, the blur from the measured rotationalrate r and applied exposure time can be calculated to select thesharpest image.

In case of exceeding the rotation rate r, another possibility is tobuffer the images of several successive flights and select the sharpestimage. The selection of the sharpest image can either be based on thecontents of the images, or on the rotational rate measured. If it isdone by the rotation rate measured, an acceptable maximum rotation ratem can be calculated using a preset upper maximum motion blur and theexposure time applied. If there is no image in a series below a presetmaximum motion blur or below the upper acceptable maximum rotationalrate m, it is also possible that none of the images is selected. Thisgives the user the opportunity to directly retry taking pictures. It isalso possible to trigger image capture events in a series only when themeasured rotational rate is below the maximum acceptable upperrotational rate m.

Further, it is intended to reduce the occurrence of blurred images byinfluencing the rotation of the camera system. To slow down and at beststop the rotation of the camera system at the apex means for detectingthe self-rotation and means for compensating for the rotation of thecamera system can be included. Known active and passive methods can beemployed to slow down the rotation.

In the active methods the control system uses a control with or withoutfeedback. For example, reaction wheels use three orthogonal wheels,which are accelerated from a resting position in opposite direction tothe ball rotation about each of the respective axis. When usingcompressed air from a reservoir e.g. 4 nozzles are mounted in the formof a cross at a position outside of the ball and two further nozzlesattached perpendicular to the 4 nozzles on the surface of the camerasystem. Electrically controllable valves and hoses connected to thenozzles are controlled by comparison with data from the rotational ratesensor.

Further, to slow down the rotation of the camera system moving weightswhich upon activation increase the ball's moment of inertia can beemployed.

As a passive method, it would be appropriate to attach e.g. wings ortail feathers outside of the camera system as aerodynamically effectiveelements.

Another method employs a liquid, a granule, or a solid body, each in acontainer, in tubes or in a cardanic suspension. These elements woulddampen the rotation due to friction.

The above mentioned and claimed and in the exemplary embodimentsdescribed components to be used in accordance to the invention are notsubject to exceptions with respect to their size, shape, design,material selection and technical concepts so that selection criteriawell-known in the art can be applied without restriction.

Further details, features and advantages of the invention's objectemerge from the dependent claims and from the following description ofthe accompanying drawings in which a preferred embodiment of theinvention is presented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a camera system according to theinvention.

FIG. 2 is a perspective view of a camera system according to theinvention.

FIG. 3 is a schematic representation of the integration of theacceleration before the beginning of the free fall with air resistance.

The embodiment according to FIGS. 1, 2 and 3 represent a camera systemfor capturing full spherical panoramas, which is thrown into the air. Itis called Throwable Panoramic Ball. Camera, and described below.

The camera system according to the invention consists of a sphericalsupporting structure 4, for example a ball, with 36 mobile phone cameramodules 1 and the necessary electronics inside. The camera modules 1 arearranged on the surface of said spherical supporting structure 4 so asto cover the entire solid angle of 4 pi sr. That is, the camera modules1 cover the entire solid angle with their view volume. The camera systemis cast vertically into the air by the user and the camera system isgiven an acceleration 7 upon launch, which is detectable by anaccelerometer 2 arranged in the camera system. After integrating theacceleration 7, and determining the velocity, the moment of reaching ofthe apex is determined. Upon reaching the apex the mobile phone cameramodules 1 simultaneously each trigger an image capture.

This happens when the hall is moving very slowly. The images of thecameras are composed to a composite image according to existing methodsfor panoramic photography.

The construction of the camera can be further described as follows. Thecamera system comprises 36 mobile phone camera modules 1 each bufferingimage data after capturing in a First-In-First-Out RAM IC (FIFO RAM-IC).The mobile phone camera modules 1 and the FIFO-RAM-ICs are mounted onsmall circuit boards below the surface of the ball to a supportingstructure 4. A motherboard with a central microcontroller and othercomponents that make up the control unit 3 is located inside thesupporting structure 4. The mobile phone camera modules 1 are connectedvia a bus to the central microcontroller. This transfers the image datavia a connected USB cable to a PC after the flight.

The flight of the camera system can be divided into four phases: 1.Rest, 2. Launch, 3 Flight, 4 Collection. In phase 1, the sensor 2measures only acceleration of gravity, while in phase 2, theacceleration due to gravity plus the bunch acceleration 7 is measured bysensor 2. The beginning of the launch phase 8 and the end of the launchphase 9 is shown in FIG. 3. During Phase 3, i.e. the flight phase, no oronly a very little acceleration is measured by sensor 2, because thesensor's test mass descends (and ascends) as fast as the camera system.In phase 4, inertia by capture adds to the acceleration of gravity.

Since the measured acceleration 7 during the flight at the end of thelaunch phase 9 is approximately 0 m/s², the apex is best determinedindirectly through the launch velocity. Therefore, the microcontrollerconstantly caches the last n acceleration values in a first-in-first-out(FIFO) buffer. The flight phase is reached when the measuredacceleration falls below the threshold value of 0.3 g for 100 ms.

To determine the launch phase, the FIFO is accessed in reverse order. Inthis case, the end of the launch phase 9 is detected first as soon asthe acceleration increases to a value over 1.3 g. Then, the FIFO is readfurther in reverse until the acceleration 7 drops below 1.2 g. Thelaunch velocity can now be determined by integrating the acceleration 7between these two time points in the FIFO, wherein the acceleration bygravity is subtracted. The integrated surface 10 is shown in FIG. 3. Theascending time to the apex is calculated directly from the velocitywhile taking into account air resistance.

The mobile phone camera modules 1 are triggered by a timer in themicrocontroller of the control unit 3, which starts upon detection offree fall with air resistance after the ascending phase. The individualtrigger delays of the mobile phone camera modules 1 are considered andsubtracted from the ascending phase as correction factors. Furthermore,100 ms are subtracted after which the free fail is detected as describedabove.

For the camera system according to the invention, a module which is assmall as possible of a mobile phone camera is used as a mobile phonecamera module 1 with fixed focus. In this type of lens, the entire sceneis captured sharply above a certain distance and does not require timefor focusing. Most mobile phone cameras have relatively low openingangles, so that more mobile phone camera modules are required in total.However, this causes the recesses 6 on the surface and supportingstructure 4 of the camera system to remain narrow. This makes unintendedtouching of the lenses when throwing less likely. Advantageously, in thecamera system, the direct compression of the JPEG image data is managedby hardware. This allows that many images are cached in the FIFO andsubsequent transfer to the PC is fast.

For enabling throwing the camera system, the spherical supportingstructure 4 needs to be kept small. Therefore, it is necessary tominimize the number of mobile phone camera modules 1 to be arranged sothat the entire solid angle is covered. This is why the position of themobile camera modules 1 on the surface of the supporting structure 4 wasoptimized numerically. For this purpose, an optimization algorithm wasimplemented, which works on the principle of hill climbing with randomrestart and the result is subsequently improved by simulated annealing.

The virtual cameras are placed with their projection centers in thecenter of a unit sphere to cover a part of spherical surface by theirview volumes. Thus, the coverage of the solid angle by the cameramodules for a given combination of camera orientations can be evaluatedby checking the uniformly distributed test points on the sphere surface.As cost function, the number of test points is used, which are notcovered by a virtual camera. The algorithm minimizes this cost function.

To be able to practically implement the computed camera orientations, itis useful to manufacture the supporting structure 4 by rapidprototyping. The supporting structure 4 was manufactured by selectivelaser sintering of PA 2200 material.

Holes in the supporting structure 4 are provided for better air coolingof electronics. To this shell suspensions are mounted inside forattaching the circuit boards of the mobile phone camera modules 1. Inaddition, suspensions are available for the motherboard and the battery.The sphere is divided into two halves, which are joined together byscrews. In addition to the holes for the camera lenses, gaps for the USBcable and the on/off switch are present. Points for attachment of ropesand rods are also provided. The suspension for the camera boards shouldallow accurate positioning of the mobile phone camera modules 1 at thecalculated orientations. It is important that by throwing the camerasystem, no change in position occurs. To ensure this, arresters weremounted on two sides of the suspension and springs on each oppositesides. The springs were realized directly by the elastic material PA2200.

In addition, a clip fastened on both sides with a hook pushes thecircuit board toward the outside of the supporting structure 4. Thearrest in this direction consists of several small protrusionspositioned on free spots on the board. On this side there is also achannel that directs the light from an LED to the outside.

Every mobile phone camera module 1 is mounted behind a recess in thesurface of the camera system. This recess is adapted to the shape of theview volume of the mobile phone camera module 1. It has therefore theshape of a truncated pyramid. In this recess positioned on one side isthe outlet of the LED channel and on the other side, recessed duringlaser sintering, the number of mobile phone camera modules 1. When usingthe camera system, it is very difficult to touch camera lenses withfingers due to the shape and size of the recesses, protecting these fromdamage and dirt.

As a shock absorber in case of accidental dropping and to increase grip,foam is glued to the outside of the supporting structure 4, which formsa padding 5. A closed cell cross-linked polyethylene foam with a densityof 33 kg/m³ is applied, which is available commercially under the brandname “Plastazote® LD33”.

FIG. 2 shows the exterior view of the camera system with padding 5, thesupporting structure 4, the recesses 6 and the mobile phone cameramodules 1.

Every mobile phone camera module 1 is positioned on a small board. Allcamera boards are connected by one long ribbon cable to the motherboard.This cable transfers both data to the motherboard via a parallel bus andthe control commands via a serial bus to the camera boards. Themainboard provides each of the camera boards via power cables withrequired voltages.

The mainboard itself hosts the central microcontroller, a USB-IC, abluetooth module, the power supply, the battery protection circuit, amicroSD socket, an A/D converter, an accelerometer, and rotational ratesensors.

On the camera board located next to the VS6724 camera module is a AL460FIFO IC for the temporary storage of data and a ATtiny24microcontroller. The camera module is mounted in the center of a 19.2mm×25.5 mm×1.6 mm size board on a base plate. This is exactly in themiddle of the symmetrical board to simplify the orientation in thedesign of the supporting structure 4. The FIFO-IC is placed on the flipside, so that the total size of the board only insignificantly exceedsthe dimensions of the FIFO-ICs. A microcontroller handles thecommunication with the motherboard and controls FIFO and camera.

NUMERAL LIST

-   1 Single cameras-   2 Sensors-   3 Control unit-   4 Supporting structure-   5 Padding-   6 Recesses-   7 Acceleration-   8 Beginning of the launch phase-   9 End of the launch phase-   10 Integrated area-   11 Actuatory components

The invention claimed is:
 1. A method of capturing images using a camerasystem comprising at least two single cameras covering together a solidangle of 4 pi sr, a control unit and two or more sensors comprising anaccelerometer and a rotation rate sensor, the method comprising:propelling the camera system by an initial acceleration to a startingvelocity; triggering the camera system when the camera system fallsshort of a minimum distance of at most 5 cm from an apogee within atrajectory of the camera system, the triggering determined according toa predetermined objective function, the apogee determined by integratingacceleration of the camera system in time before entry into free fallwith air resistance; capturing at least a single image by the two singlecameras; and further comprising defining a maximum motion blur andcalculating a maximum rotational rate r using exposure time applied andtriggering the at least two single cameras by comparing values of therotation rate sensor to the maximum rotational rate r by the controlunit.
 2. A method of capturing images using a camera system comprisingat least two single cameras covering together a solid angle of 4 pi sr,a control unit and two or more sensors comprising an accelerometer and arotation rate sensor the method comprising: propelling the camera systemby an initial acceleration to a starting velocity; triggering the camerasystem when the camera system falls short of a minimum distance of atmost 5 cm from an apogee within a trajectory of the camera system, thetriggering determined according to a predetermined objective function,the apogee determined by integrating acceleration of the camera systemin time before entry into free fall with air resistance; capturing atime series of images, each comprising at least a single image capturedby the single cameras; and further comprising defining a maximum motionblur and calculating a maximum rotational rate r using exposure timeapplied and triggering the at least two single cameras by comparing thevalues of the rotation rate sensor to the maximum rotational rate r bythe control unit.
 3. The method of capturing images using a camerasystem according to claim 2, further comprising evaluating and selectingan image by the control unit depending on the content of the images. 4.The method of capturing images using a camera system according to claim2, further comprising evaluating and selecting an image by the controlunit by the measured values of the sensors.
 5. The method according toclaim 3, comprising selecting the image from the time series of imagesby calculating the current position of the camera system from theimages.
 6. The method according to claim 3, comprising selecting theimage from the time series of images by the sharpness of the images. 7.The method according to claim 3, comprising selecting the image from thetime series of images by the size of compressed images.
 8. The methodaccording to claim 1, wherein the single cameras are synchronized witheach other so that they all trigger at the same time.
 9. The methodaccording to claim 1, wherein the triggering of the single cameras doesnot occur when the maximum rotational rate r is exceeded.
 10. The methodaccording to claim 1, wherein upon exceeding the maximum rotation rater, buffering images of a plurality of successive flights and selectingonly one of the images by the control unit using an upper maximumrotation rate m and a rotation rate, wherein an upper maximum rotationrate m is calculated from a predetermined upper maximum motion blur andexposure time applied.
 11. The method according to claim 1, comprisingthe central control unit acquiring exposure-related data from thesensors or arranged single cameras with the beginning of the flight,determining matching exposure settings for the single cameras andsending these to the single cameras and the single cameras at thetrigger time using exposure settings from the control unit instead oflocal settings for single image capture.
 12. The method according toclaim 1, comprising the central control unit acquiring focusing-relateddata from the sensors or arranged single cameras with the beginning ofthe flight, determining matching focusing settings for the singlecameras and sending these to the single cameras and the single camerasat the trigger time using focus settings from the control unit insteadof local settings for single image capture.
 13. The method according toclaim 1, comprising the central control unit before the beginning of theflight determining the direction of the gravity vector relative to thecamera using an orientation sensor, determining the orientation changebetween the time of this measurement and the trigger point, anddetermining the gravity vector at the moment of triggering using thegravity vector determined before the beginning of the flight and thechange in orientation.
 14. The method according to claim 2, wherein thetriggering of the single cameras does not occur when the rotational rater is exceeded.
 15. The method according to claim 2, wherein uponexceeding the rotation rate r, buffering images of a plurality ofsuccessive flights and selecting only one of the images by the controlunit using an upper maximum rotation rate m and a rotation rate, whereina maximum rotation rate m is calculated from a predetermined uppermaximum motion blur and an exposure time applied.
 16. The methodaccording to claim 2, comprising the central control unit before thebeginning of the flight determining the direction of the gravity vectorrelative to the camera using an orientation sensor, determining theorientation change between the time of this measurement and the triggerpoint, and determining the gravity vector at the moment of triggeringusing the gravity vector determined before the beginning of the flightand the change in orientation.
 17. The method according to claim 2,comprising the central control unit acquiring exposure-related data fromthe sensors or arranged single cameras with the beginning of the flight,determining matching exposure settings for the single cameras andsending these to the single cameras and the single cameras at thetrigger time using exposure settings from the control unit instead oflocal settings for single image capture.
 18. The method according toclaim 2, comprising the central control unit acquiring focusing-relateddata from the sensors or arranged single cameras with the beginning ofthe flight, determining matching focusing settings for the singlecameras and sending these to the single cameras and the single camerasat the trigger time using focus settings from the control unit insteadof local settings for single image capture.